1. Field of the Invention
Fried foods, for example, omelets, are widely prepared. Always present are the problems of food sticking to the frying surface and the venting of cooking gases in a closed system. In moving the food frying process from the home kitchen into the commercial and institutional large scale kitchen, there is the further need for structure that will withstand constant and intensive use. A material component of any frying system is the device in which the food is fried, and that device must be capable of intensive and sustained use for long periods of time.
Recent commercial and institutional techniques for roasting foods, such as omelets, call for the frying under pressure of egg liquid combined with seasoning and vegetables. This is accomplished by placing egg liquid in a frying device, frying it and placing a weight on top of the omelet after it has sufficiently solidified.
2. Description of the Prior Art
A. Prior Art Of Others
Conventional frying devices present problems solved by my invention in utilizing prior apparatus and methods for several reasons.
It is known that when foods are fried in a pan without a cooking oil or similar substance, the food will stick to the frying surface.
In the prior art, such sticking may in some cases be prevented by coating the pan with Polytetrafluroethylene (Teflon). Teflon is a trademark of DuPont. However, after continued and intensive use, the Teflon coating will fade and wear out. In intermittent and continuous commercial mass-production use of Teflon-coated roasting pans, the pans wear out in about three months. Additionally, frying devices known to me have not been provided with means to permit the escape of cooking gases while frying directly from the material being fried to the atmosphere. Thus, when foods are fried under pressure, cooking gases may build up and create a safety hazard.
Additionally, although many frying pans are made of iron, iron is extremely heavy and has extremely high thermoconductivity. Finally, any non-Teflon pan requires the reapplication of considerable amounts of surface oils.
A commercial process for producing a folded egg omelet is disclosed in U.S. Pat. No. 3,753,737 to Latham et al. But that process only discloses a folded, and not a layered, omelet; it discloses an omelet pan of stainless steel and teaches no special means for venting cooking gases other than stopping the process (Col. 7, lines 33 ff.) and exposing the entire pan to the air during frying. Further, this process cannot produce an evenly compressed cooked omelet since there is no teaching of a weight used during cooking. Finally, no special appearance or method is disclosed to prevent the sticking of the omelet during the cooking process.
U.S. Pat. No. 3,732,114 to Field teaches a method of producing a laminated frozen food product. Field uses a thin film of heattransfer lubricant to remove heat from the food product and freeze it. Field has nothing to do with cooking and does not discuss or solve the problem of food being fried sticking to any cooking device due to the thermoconductivity of the frying device or discuss or solve the problem of venting the omelet during frying.
The prior art also discloses several devices that can be utilized as frying devices. U.S. Pat. Nos. 993,169 to Hudson, 1,010,887 to French, 1,072,892 to Wilson, and 1,292,476 to Kavanagh, for example, all show hinged frying pans suitable for making omelets, but none of these patents teach, show or suggest any structure or method for preventing sticking of the food being fried, or lowering thermoconductivity, or venting of the gases produced, while cooking. These two goals must be achieved in any device used in the institutional and commercial mass production of fried foods such as omelets. A device similar to those shown in the afore-mentioned patents is U.S. Pat. No. 2,696,161 to Hicks for cooking wieners in waffle dough.
A device that does disclose some structure for venting cooking gases is disclosed in U.S. Pat. No. 1,874,836 to Trenner et al. Trenner relates to baking of pies and pie shells, not frying, but the vents shown in the device disclosed are to allow condensible vapors to escape. Importantly, the vents disclosed do not vent directly from the product being cooked to the atmosphere, but to the bakery oven and, importantly, the interior vent surfaces do not directly contact the material being cooked. Further, Trenner discloses no structure or method to prevent sticking or lower thermoconductivity.
U.S. Pat. No. 2,174,425 to Schlumbohm disclose a very thin metal foil fry pan that is designed to be used only once and then thrown away and disposed of. It is not to be reused. Schlumbohm attributes any improved nonsticking qualities of his device to the highly polished surface. Importantly, the recesses and grooves disclosed do not serve as vents (they are to be filled with fat, see Col. 2, line 43 ff.) and are places where food being fried could stick. Thermoconductivity is high. Any vents disclosed are from the outer of a set of walls.
U.S. Pat. No. 3,007,595 to Remley describes a multiple-recess cooking utensil having two complementary pan members joined by a hinge structure. The pores, although described as preferably of uniform cast construction, are not described as including pores and cavities. Further, the pans are not described as being cast of a low pressure of an aluminum alloy so as to form the desired cavities or pores.
U.S. Pat. No. 2,618,258 to Kroyer relates to cooking utensils having a frying surface provided with a multitude of rounded depressions with rounded tops therebetween. The frying surface as a whole has an undulated, dimply or rippled appearance substantially similar to that of hammered silverware (note column 2, lines 10-13). The depressions are described as having a diameter of about 1/8-3/8 inch (column 3, lines 14-15), well outside the range of my invention. Further, the arrangement of Kroyer is described as reducing the danger of scorching the food being fried and thus cannot properly be considered a teaching of providing much smaller cavities or pores to prevent sticking of food being cooked.
Kroyer also describes (column 3) producing his utensil of aluminum and forming a coating of reduced heat conductivity by anodically oxidizing the aluminum to form a rippled surface with dimensions of a quite different order of my invention. My invention defines the fry member as cast under low pressure from aluminum alloy of a certain type to form the porous frying surface.
U.S. Pat. No. 1,216,973 to Epprecht describes a frying pan having a bottom provided with a plurality of closely arranged, minute depressions serving as wells for fat to prevent scorching of food being fried. The depressions may be formed by stamping or by casting, but Epprecht does not describe casting the pan under low pressure and from an aluminum alloy.
U.S. Pat. No. 264,867 to Ege describes a broiler formed of two hinged plates having embossments to afford sufficient intermediate spaces for the retention of the juices of the meats or other substances placed thereon. The material used in he manufacture of the plates is preferably sheet metal and the embossments are not described as being within the size range of my invention or produced from casting an aluminum alloy of low pressure.
B. Prior Art Of Mine
Other prior art includes my British Patent Specification No. 1 511 407, Canadian Pat. No. 1069324, Brazilian Pat. No. 7605736, French Certificat D'Utilite No. 76 26497, German Pat. No. 26 41 20 and Japanese Application No. 46,785/1976.
While this prior art generally describes a porous material composed of aluminum or a metallic compound or a ceramic, there is no teaching or suggestion in any of that prior art of what I have found to be true in the apparatus of this invention, namely the use of aluminum alloy with specific ranges of certain component or the casting formed under a low pressure of 1 (one) atmosphere as described hereinafter and the formation of pores and cavities in the casting of a defined size range.
For example, in my Canadian Pat. No. 1069324 it is stated that there is no limitation in the "size . . . of the holes or slits in the side walls of the pan elements (page 4, lines 30-31)." This refers to the body of the frying device. In fact, in all of my prior art patents, all dimensions stressed and defined are the dimensions of the holes in the specific form of the invention using a weight number and are dimensions for the holes in the weight member, not in the walls or bottom of the fry member, (see, e.g., British Pat. No. 1,511,407, p. 2, lines 48'50; Canadian Pat. No. 1069324, p. 3, line 19).